Minimize Residual Energy of the 3-D Underwater Sensor Networks with Non-uniform Node Distribution to Prolong the Network Lifetime

Underwater sensor networks (UWSNs) have caused wide-spread concern of academia due to their wide range of applications. Efficient energy depletion and avoiding energy holes are the important issues. In this paper, we study on the theoretical aspects of the non-uniform node distribution strategy in the 3-D underwater environment, which aim to mitigate the energy holes and balance energy depletion of nodes in the 3-D underwater sensor networks. Based on extensive analysis and theoretical proofs, the absolute balanced energy depletion in the whole underwater sensor networks is not achievable, while the maximized balanced energy depletion except for the nodes in the outermost (Annular Globular Region) is possible. Furthermore, we propose a non-uniform distribution routing algorithm based the minimum energy consumption called MEC to address the energy hole problems and prolong the network lifetime. Extensive simulations show that the network achieves a high energy efficiency, less than 5% of total initial energy is wasted and the network lifetime is prolonged more than 400% compared with the uniform node distribution strategy.